Editor's note: John Avlon is a CNN contributor and senior political columnist for Newsweek and The Daily Beast. He is the author of "Wingnuts: How the Lunatic Fringe Is Hijacking America."

(CNN) -- The cycle of incitement continued this week as Democrats frustrated with the debt-ceiling deal equated the tea party with terrorists, just weeks before the 10th anniversary of 9/11.

It is an ugly and unacceptable comparison, especially coming -- as it did -- on the heels of U.S. Rep. Gabrielle Giffords' triumphant return to Congress after being shot in Tucson in January.

The instinct to raise funds off fear-mongering was also deployed in record time, as GOP presidential hopeful Michele Bachmann -- no stranger herself to the politics of incitement -- fired off an e-mail which read: "The Democrats have stooped to a new low. This afternoon, Vice President Joe Biden reportedly led a congressional meeting where tea party members were labeled as 'terrorists.' "

Biden was falsely implicated in initial reports, and on CBS' Face the Nation, Biden said: "What happened was there were some people who said they felt like they were being held hostage by terrorists...I never said that they were terrorists or weren't terrorists, I just let them vent." He added: "I said even if that were the case, what's been happening when you now have taken and paid the debt and move that down so we can now discuss, the nuclear weapon's been taken out of anyone's hands."

In the same time frame, newly minted New York Times columnist Joe Nocera fired off a piece, "The Tea Party's War on America," centered on the same theme. Among the more explicit imagery deployed was this: "The tea party Republicans can put aside their suicide vests." He apologized in a column Friday.

Talking about "hijacking" debates is an acceptable part of political discourse -- a vivid metaphor for a vocal minority taking control of the entire ship of state. Extending that to comparisons with terrorists -- who by definition kill innocent civilians -- is a bridge way too far. Conservatives were rightly upset at the relative lack of media outrage about these statements that might have been broadly denounced if they came from a sign at a conservative populist rally.

In this case, it was fascinating to see the debate descend into screeds about terrorist tactics: "Trying to save the world as we know it today" (that was Pelosi) and "Satan sandwiches" (I have no idea what that is). After all, this was a policy debate over the debt; a fight over funding, albeit with default hanging in the balance.

As James Piereson, senior fellow at the Manhattan Institute and author of a book on John F. Kennedy and American liberalism, told me: "The out-of-control rhetoric directed against the tea party is truly bizarre, especially given the fact that it was provoked by a complex budget debate that few Americans even understand, including those tossing about terms like 'terrorist' and 'jihad.' Temper tantrums and name-calling are rarely helpful in advancing understanding and good policy."

He's right. But this hair-trigger cycle of characterizing political opponents as personal enemies and demonizing people who disagree with you has proliferated, as the two parties have become more ideologically polarized. Talking about the apocalyptic intentions of the other side has become part of the fundraising pitch and national political conversation, pumped up through partisan media. With that has come a pervasive tendency to excuse or ignore extreme statements that come from your side of the aisle. The rationalization seems to be "they may be crazy; but they're our crazies," offered with a wink and a nod.

Michele Bachmann in particular has made the cycle of incitement a profitable sideline, playing politics by talk radio rules in which there is no such thing as too extreme. A standard-part of Bachmann's repertoire is warning of the president's determination to impose "tyranny" and "slavery" on the American people. This fear-mongering helped her to raise $13.5 million in national activist cash, while playing the victim card whenever she was called on her tactics.

Both Michele Bachmann and DNC Chair Debbie Wasserman Schultz used the term "dictator" to describe their political opponents on the same day last week. The two gaffes were almost unremarkable in the current spin cycle -- part of the scenery.

Terrorist comparisons have surfaced since the '08 campaign, when -- to use just one example -- Iowa Congressman Steve King declared, "If (Obama) is elected president, then the, the radical Islamists, the, the al Qaeda, and the radical Islamists and their supporters, will be dancing in the streets in greater numbers than they did on September 11."

Sarah Palin's accusation during the '08 campaign that Barack Obama was "palling around with terrorists" referred to his acquaintance with Bill Ayers, but the implications were far broader.

And when it comes to fear-mongering as policy re-framing, Palin's raising the specter of government "death panels" that would sentence your parents and children to execution remains a memorable low.

But the conservative outrage over the recent "tea party = terrorists" rhetoric also seemed to be tinged with a satisfied sense of hypocrisy-hunting. After all, President Obama and the Democrats were the ones who called for a "new tone" after the shooting of Gabby Giffords, a call for civility that was much-mocked on right-wing talk radio at the time. For example, Rush Limbaugh, who after the Giffords shooting announced "Civility is the new censorship" now greeted news of the Democrats' comparison by asking semi-sarcastically "Where is the civility?"

This is, of course, the man who calls President Obama 'imam child.' Behind the outrage seemed to be a sense of vindication of the view that this is the way politics is run in practice and aspirations toward civility are naïve at best -- that it's time to embrace gutterball as the new normal.

So how will this cycle of incitement stop? It will only happen if responsible Republicans and Democrats start standing up to the extremes of their own party as a matter of principle.

The godfather of the modern conservative movement, William F. Buckley Jr. famously stood up to the John Birch Society founder Robert Welch after he published a book alleging that President Eisenhower was a Soviet spy. He understood that extremists were ultimately their own side's worst enemy and that unhinged attacks reflected badly on the broader movement he was trying to build.

But in our time, we rarely see such moments of courage rewarded. Instead, standing up to the extremes in one's own party usually is greeted with a talk of primary challenge and over-heated accusations of disloyalty. This is part of what happens with polarization -- the fringe starts to blur with the base. The impulse to play to the lowest common denominator and pander to special interests starts to crowd out considerations of the national interest.

We need a reset in American politics -- and that will only happen when Democrats and Republicans are willing denounce extreme statements and professional polarizers on their side of the aisle. This is not evidence of moral equivalence. It is an attempt at moral clarity.